Science Paper on Hubble Space Telescope Hale-Bopp Results

Science Paper on Hubble Space Telescope Hale-Bopp Results

Figure 1 from the Science paper: HST images of Hale-Bopp on 8 different
dates. All images were interpolated to the same spatial scale of 470
km/pixel (each image covers a distance of ~33,000 km at the comet),
normalized to the same peak pixel intensity, and are displayed using the
same logarithmic intensity scale. In all images, celestial north is straight
up (vertical direction) and east is to the left. The image from 26 September
1995 was taken ~60 hrs after a strong dust outburst and shows a spiral arm
wrapping around the nucleus. The images in the fall of 1996 show multiple
jets that are presumably connected to the activation of multiple vents on
the surface of the nucleus. The image from 7 April 1996 was slightly trailed
due to poor tracking.

The same as Figure 1 above, except using a different color stretch so that
the core of the image is a little "bloomed out". Most people find this
version to be a bit more visually pleasing than the one above. However, the
image in Figure 1 is scientifically more valuable.

This is an HST image of Hale-Bopp taken on 26 September 1995 with the WFPC2
in wide-field camera mode. The frame is about 10 arcsec across, which
corresponds to 47,000 km at the comet. Serendipitously, we caught the comet
only ~60 hrs after a large outburst, and we see the magnificent spiral arm
that results.

This is an HST image of Hale-Bopp taken on 23 September 1996 with the WFPC2
in planetary camera mode. The frame is 10.9 arcsec across, which corresponds
to 23,360 km at the comet. The shape of the coma at this time is very
different from what was observed a year earlier (in 1995). Instead of seeing
a single strong jet and its associated spiral structure, the comet now has
sprouted several jets, making it look more like a porcupine.

This is the same data as for the preceeding image, except that we divided by
an azimuthally-averaged Hale-Bopp image. This technique emphasizes the jet
structure and also removes the steep brightness drop-off as you move away
from the nucleus.

In this image, the nucleus is at the very center of the frame, just below
and to the right of the very strong jet near 11 o'clock. Apparently there
was an outburst in this direction shortly before our observations. Farther
out there is another bright region that must be the remnant of an even
earlier outburst. Several weaker jets (at 10 o'clock, 7:30, 3 o'clock, and 1
o'clock; celestial North is at 12 o'clock and East is at 9 o'clock) are also
visible. This image demonstrates graphically that Hale-Bopp's nucleus must
be a very dynamic place. The frame is 10.9 arcsec across, which corresponds
to 23,360 km at the comet during these September 1996 observations. The
length of the "white" jet emanating at 11 o'clock is 0.96 arcsec (2050 km at
the comet).